Die member in a cross-head die apparatus

ABSTRACT

A cross-head die for applying one or more layers of coating materials to a single, longitudinally fed, filamentary member, or to a plurality of such members in spaced, side-by-side relation. Tip and die members of relatively flat, wafer-like configuration are placed in a cylindrical cavity of the body member of the apparatus with central openings in each of the tip and die members coaxially arranged and a protrusion surrounding the opening in the tip extending into the opening in the die. Flowable coating material is injected through a radial opening in the body member and flows in both directions about an annular passageway formed by cooperatively arranged grooves in the peripheries of the tip and die members. The coating material flows from the annular passageway to the die aperture through opposing, spaced, angularly arranged surfaces on the tip and die members. In an embodiment for applying two layers of coating material, two tip members and a single die member, all of wafer-like configuration are employed, and in an embodiment for coating multiple members the apertures in the tip and die are of oblong configuration.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a division of application Ser. No.08/630,635, filed Apr. 10, 1996, now U.S. Pat. No. 5,679,157 which was adivision of application Ser. No. 08/320,329, filed Oct. 11, 1994 nowU.S. Pat. No. 5,674,318, filed Oct. 7, 1997.

BACKGROUND OF THE INVENTION

The present invention relates to the class of extruding apparatuscommonly known as cross-head dies. One or more electrical wires or otherelongated, filamentary members are moved axially through such apparatusas a flowable coating material is injected therein, and the coatingmaterial is applied in one or more substantially concentric layers tothe filamentary member(s) as it exits the apparatus. This is theconventional manner of applying, for example, a plastic insulating layerto an electrical wire.

Prior art cross-head die apparatus is typified by that disclosed in thepresent inventor's U.S. Pat. Nos. 5,031,568 and 5,316,583, andreferences cited therein. In such apparatus, a plurality of elements arecooperatively positioned within an axial bore of the body, and moltenplastic is introduced through a radial bore. The elements are maintainedin the desired relationship by mating, conically tapered surfaces. Inthe apparatus of the aforementioned U.S. Pat. No. 5,031,568, in additionto the body and threaded cover, there are four internal elements, namelya tip holder, a die tip, a die and a die holder. In the apparatus ofU.S. Pat. No. 5,316,583, only three internal elements are required, atip holder, die tip and die. In each case, the disclosed apparatusapplies a single layer of coating material to the wire.

As a general rule, it is desirable to minimize the number of elements ina cross-head die, as with other structural assemblies, since the partsreduction normally results in cost savings. Also, assembly anddisassembly time, frequency of breakdowns and parts replacement, etc.likewise may be expected to benefit from reduction of the number ofparts. This assumes, of course, that the speed of operation, quality offinal product, and the like, are not compromised by elimination ofcertain parts. In particular, in operation of a cross-head die, it isessential to distribute the molten coating material evenly about theaxially moving filamentary member.

Accordingly, it is a principal object of the present invention toprovide a cross-head die assembly for applying a layer of coatingmaterial to a filamentary member moved axially through the die whereinthe number of parts in the assembly is less than in prior art assembliesof the same class of apparatus.

Another object is to provide a cross-head die of simplified design andgenerally lower cost than prior art apparatus of the same type.

A further object is to provide novel and improved tip and die elementsfor use in cross-head dies.

Still another object is to provide cross-head die apparatus includingmeans for easily removing internal elements from an axial bore in thedie body.

Other objects will in part be obvious and will in part appearhereinafter.

SUMMARY OF THE INVENTION

The cross-head die of the present invention includes the usual bodymember having a through axial bore for passage of a filamentary memberto be coated and a radial bore through which molten plastic or otherflowable coating material is supplied to the axial bore for applicationto the filamentary member. In an embodiment for applying a single layerof coating material to the filamentary member, a tip member and a diemember are positioned within the axial bore of the body. Each of the tipmember and die member has a circular periphery for mating with the axialbore of the body, and is of relatively flat, wafer-like configuration.The tip and die members each have central openings, that of the tipmember surrounded by a protrusion which extends into and through thecentral opening in the die member. The member to be coated has adiameter closely approximating that of the opening in the tip memberwhich thus serves to maintain axial alignment of the filamentary memberas it passes through the apparatus.

The tip and die members are positioned in coaxial relation with oneanother and with the axial bore of the body, wherein they are retainedby a threaded cover member. Pins extend from a flat surface of the tipmember into openings in the opposing surface of the die member tomaintain a desired rotational orientation of the members relative to oneanother. A separate pin extends either radially or axially into the bodyto engage a notch or opening in one or both members to maintain adesired rotational orientation of the members relative to the axial borein the body.

Peripheral grooves in the opposing surfaces of the tip and die memberscombine to form a unitary groove of semicircular cross section which,together with an adjacent portion of the surface of the axial bore inthe body forms an enclosed passageway extending partially around the tipand die members. The center of this passageway is adjacent the inner endof the radial bore in the body, whereby the coating material enters thepassageway and flows in both directions around the periphery of the tipand die members. On diametrically opposite sides, the passageway mergeswith surface portions of the tip and die members which taper inwardlyfrom the peripheral edges to the central protrusion. Coating materialflows from opposite sides of the peripheral passageway, over thesetapered surfaces and through an annular space between the tip memberprotrusion and the opening in the die member where it is deposited onthe filamentary-member moving axially through the apparatus.

In a second embodiment, the cross-head die is adapted to apply twolayers of coating material, one layer covering the other, to thefilamentary member. Two radial bores in the body communicate with theaxial bore on diametrically opposite sides and are axially spaced alongits length. Three members, termed a first and a second tip member and adie member, of the same general wafer-like configuration as the tip anddie member of the first embodiment, are positioned coaxially within theaxial bore and retained by a threaded cover member. The first tip memberand the die member are positioned on opposite sides of the second tipmember with flat, parallel, opposite surface portions of the second tipmember contacting like surface portions of the first tip member and thedie member. Locator pins maintain the desired rotational orientation ofthe members relative to one another and to the axial bore of the body,as in the first embodiment.

The first and second tip members have peripheral grooves in theiropposing surfaces forming a first, unitary groove of semicircular crosssection which, together with portions of the body axial bore form afirst, enclosed passageway extending around first portions of theperipheries of the first and second tip members. The opposing surfacesof the second tip member and the die member also have adjacentperipheral grooves forming a second, unitary groove which, together withportions of the body axial bore form a second, enclosed passagewayextending around second portions of the peripheries of the second tipmember and the die member.

Opposing surface portions on opposite sides of the first and second tipmember communicate with opposite ends of the first passageway and taperinwardly from the periphery toward the center of the members. The centerof the first passageway is adjacent the inner end of one of the radialbores in the body. A first coating material flows through this radialbore, in both directions around the first passageway, and through thespaces between the opposed, tapered surfaces on each side of the two tipmembers.

Opposing surface portions of the second tip member and the die membertaper inwardly from the periphery toward the center on each side. Thesecond passageway communicates at opposite ends with the spaces betweenthe tapered surfaces. A second coating material flowing through theother radial bore in the body enters the second passageway at its centerand flows in both directions around the second tip member and the diemember, into the spaces between their opposing, tapered surfaces. Boththe first and second tip members have axially extending protrusionssurrounding central openings and the die member has a central openinginto which these protrusions extend.

The first coating material flows from the spaces between the opposing,tapered surfaces of the first and second tip members through an annularspace between the outer surface of the protrusion on the first tipmember the opening in the second tip member to be deposited in coveringrelation to a filamentary member traveling axially through the die body.The second coating material flows from the spaces between the opposed,tapered surfaces of the second tip member and the die member through anannular space between the outer surface of the protrusion on the secondtip member and the opening in the die member to be deposited in coveringrelation to the layer of first covering material. Thus, the filamentarymember is coated with two concentric layers of coating materials.

A further disclosed embodiment illustrates how principles of theinvention may be utilized in the application of continuous coatings to aplurality of spaced, parallel filamentary members, as in so-called flatribbon cables. In all embodiments, the tip and die members may be easilyremoved from the axial bore of the body by removing the cover andadvancing a threaded member into the opposite end of the bore.

The foregoing and other features of the structure and operation of thecross-head die apparatus of the invention will be more readilyunderstood and fully appreciated from the following detaileddescription, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view of a first disclosed embodimentof the cross-head die of the invention;

FIG. 2 is a side elevational view of the die of FIG. 1, showing theelements in assembled relation, the upper half and a fragment of thelower half being in section through the vertical centerline;

FIG. 3 is a side elevational view of one of the elements of FIGS. 1 and2;

FIG. 4 is a rear elevational view of the element of FIG. 3;

FIG. 5 is a side elevational view in section on the line 5--5 of FIG. 4;

FIG. 6 is a side elevational view of another of the elements of FIGS. 1and 2;

FIG. 7 is a front elevational view of the element of FIG. 6;

FIG. 8 is a side elevational view in section on the line 8--8 of FIG. 7;

FIG. 9 is a sectional, side elevational view showing in assembledrelation the two elements as seen in FIGS. 5 and 8;

FIG. 10 is an exploded, perspective view of a second embodiment of theinvention;

FIG. 11 is a side elevational view of the die of FIG. 10, showing theelements in assembled relation, the upper half and a fragment of thelower half being shown in section through the vertical centerline;

FIG. 12 is a side elevational view of one of the elements of FIGS. 10and 11;

FIG. 13 is a rear elevational view of the element of FIG. 12;

FIG. 14 is a side elevational view in section on the line 14--14 of FIG.13;

FIG. 15 is a side elevational view of another of the elements of FIGS.10 and 11;

FIGS. 16 and 17 are front and rear elevational views, respectively, ofthe element of FIG. 15;

FIG. 18 is a side elevational view in section on the line 18--18 of FIG.16;

FIG. 19 is a side elevational view of another of the elements of FIGS.10 and 11;

FIG. 20 is a front elevational view of the element of FIG. 19;

FIG. 21 is a side elevational view in section on the line 21--21 of FIG.20;

FIG. 22 is a sectional, side elevational view showing in assembledrelation the three elements as seen in FIGS. 14, 18 and 21;

FIG. 23 is a perspective view of a pair of elements embodying anotherembodiment of the invention; and

FIG. 24 is a top plan view of the elements of FIG. 23, shown in anoperative position and in section on the line 24--24 of FIG. 23.

DETAILED DESCRIPTION

The invention is illustrated, and will be described, in threeconstructions or embodiments, one for applying a single coating layer toa single filamentary member, one of applying a plurality of coatinglayers to a single filamentary member, and one for applying a singlecoating layer to a plurality of filamentary members. Throughout thebalance of the specification, the filamentary member will be referred tofor convenience as a wire, although it will be understood that thecross-head die of the invention may by utilized to apply coatings notonly to electrical conductors but also to optical fibers and otherelongated, filamentary members which are moved axially through theapparatus.

Referring now to the drawings, in FIGS. 1 and 2 are seen the elements ofa first embodiment of a cross-head die apparatus, denoted generally byreference numeral 10, incorporating features of the present invention.Apparatus 10 comprises body portion 12, tip member 14, die member 16 andcover portion 18. Also shown in FIGS. 1 and 2 are locator pin 20, itsretaining screw 22, and threaded element 24, the functions andoperations of which will be described later.

An axial bore extending through body portion 12 includes forward,threaded portion 24, intermediate, smooth portion 26 and rear, threadedportion 28, of successively smaller diameter. Portions 24 and 26 areseparated by radially extending surface portion or shoulder 30, andportions 26 and 28 are separated by shoulder 32. Radial bore 34communicates with portion 26 of the axial bore and is threaded forconnection thereto of the end of a pipe or conduit (not shown) of thetype conventionally used to supply molten plastic or other flowablecoating material to cross-head dies. Radial bore 36 also communicateswith the axial bore on the side diametrically opposite radial bore 34.As seen in FIG. 2, radial bore 36 includes an inner portion throughwhich pin 20 extends, and an outer, threaded portion wherein retainerscrew 22 is threadedly inserted. Radial bore 38 and a like radial boreon the opposite side of body portion 12 are provided for connection ofthe apparatus to support means in conventional fashion.

Tip member 14 and die member 16 are of circular, relatively flat form,having what is termed a wafer-like configuration since their thicknessis a fraction (e.g., 3/16) of their diameters. In the assembledcondition, as seen in FIG. 2, tip and die members 14 and 16 have equaldiameters approximately equal to the diameter of axial bore portion 26and a combined thickness approximately equal to the axial length of boreportion 26. Tip and die members 14 and 16 are positioned within axialbore portion 26 and are maintained in a desired rotational orientationrelative to one another by pins 40 and 42 extending from surfaceportions 44 and 46, respectively, of tip member 14 into openings 48 and50, respectively, of die member 16. Tip and die members 14 and 16 aremaintained in a desired rotational orientation with respect to axialbore portion 26 by pin 20 extending into notches 52 and 54 in theperipheries of tip and die members 14 and 16, respectively.

Tip member 14 is shown individually in FIGS. 3-5, wherein theaforementioned features may be more clearly seen. In addition, it willbe seen that tip member 14 has a central opening 56 which tapersinwardly from flat, rear surface 58 to a portion of constant diameterd₁. The forward portion of opening 56 is surrounded by tip or protrusion60 which has an outer diameter d₂ at its terminal end. A portion of theperiphery of tip member 14 is cut away to form groove 62 which, as bestseen in FIG. 3, is of arcuate cross section and extends from forwardsurface portion 44 to cylindrical surface portion 64. Groove 62 extendsfrom a mid-point adjacent pin 40 in both directions about the peripheryof tip member 14 to meet surface portions 66 and 68 on opposite sides ofopening 58. As best seen in FIG. 5, surface portions 66 and 68 taper ina direction toward the forward side from the outer periphery of the tipmember to merge with the base of protrusion 60.

Die member 16 is shown individually in FIGS. 6-8. In addition to theearlier described features, die member 16 is seen to have centralopening 70, having a diameter d₃ at rear surface portions 72 and 74, anda diameter d₄ at front surface 76. Groove 78 extends in an arcuatesurface from rear surface portion 72 to cylindrical peripheral surface80, and from a mid-point adjacent opening 48 in both directions aboutthe periphery of die member 16 to merge with surface portions 82 and 84on opposite sides of opening 70. Surface portions 82 and 84 taper in adirection toward the rear side from the periphery of the die membertoward opening 70. It will be noted that opening 70 has sections ofrelatively short axial length immediately adjacent both the front andrear surface portions which are of constant diameter and which mergewith a central conical or tapered section at opposite ends of thelatter. Peripheral notch 86 is diametrically opposite the midpoint ofgroove 78.

In the assembled condition, forward surface portions 44 and 46 of tipmember 14 are in contact with rear surface 76 of die member 16, withpins 40 and 42 extending into openings 48 and 50, respectively. Thisplaces notches 52 and 86 adjacent one another so that when the tip anddie members are placed within section 26 of the axial bore androtationally oriented with the peripheral notches adjacent the inner endof radial opening 36, pin 20 extends into the notches, as seen in FIG.2, and maintains this orientation. When so oriented, grooves 62 and 78combine to form a unitary groove of essentially semi-circular crosssection, denoted in FIGS. 2 and 9 by reference numeral 88, the mid-pointof which is adjacent the inner end of radial opening 34. Protrusion 60extends through opening 70, forming an annular space between the outersurface of the protrusion and the surface of the opening adjacent frontsurface 76 of die member 16 since diameter d₄ is larger than diameterd₂.

Tapered surface portions 66 and 84 are in spaced, opposed relation, asare surface portions 68 and 82. Unitary groove 88 and the adjacentportion of axial bore section 26 form an enclosed passageway extendingfrom the mid-point of the groove in both directions about the peripheryof the tip and die members to the spaces between the opposed, taperedsurfaces on both sides. Thus, coating material entering through radialopening 34 (or the conduit connected thereto) flows through theenclosed, peripheral passageway and through the spaces between surfaceportions 66 and 84 and surface portions 68 and 82 to exit through theannular space between protrusion 60 and opening 70 to be depositeduniformly on the surface of a wire moving axially through opening 56.

The outer portion of rear surface 58 of tip member 14 is maintained incontact with surface 32 within the body portion axial bore by threadedadvance of cover portion 18 into contact with surface 30 and thus withthe outer portion of front surface 76 of die member 16. Cover portion 18is advanced into and removed from threaded portion 24 of the axial boreby a spanner wrench engaged with an opposite pair of openings 90(FIG. 1) of cover portion 18. When it is desired to remove the tip anddie members from the axial bore, cover portion 18 is removed andthreaded element 24 is advanced into threaded portion 28 to push the tipand die members out of the forward end of the axial bore. Although bothcover portion 18 and threaded element 24 are shown engaged in threadedportions 24 and 28, respectively, in FIG. 2, it will be understood thatonly cover portion 18 will be so positioned during normal operation ofthe apparatus and element 24 will be advanced into the axial bore onlyafter removal of cover portion 18.

Turning now to FIGS. 10-21, there is illustrated cross-head dieapparatus, denoted generally by reference numeral 100, wherein theprinciples of the invention are employed in applying two, superposedlayers of coating material to a single wire. Apparatus 100 includes bodyportion 102, first tip member 104, second tip member 106, die member 108and cover portion 110. As in the first embodiment, an axial boreextending through body 102 has a forward, threaded portion 112,intermediate, smooth portion 114 and rear, threaded portion 116.Portions 112 and 114 are separated by a shoulder or surface 118, andportions 114 and 116 are separated by surface 120. Radial bores 122 and124 extend through body 102 to communicate at their inner ends withaxial bore portion 114 at axially spaced positions, as best seen in FIG.11.

First and second tip members 104 and 106, and die member 108 are ofessentially the same wafer-like configuration as previously describedtip and die members 14 and 16. In the assembled condition, as seen inFIG. 11, members 104, 106 and 108 have equal diameters approximatelyequal to the diameter of axial bore portion 114 and a combined axialthickness approximately equal to the axial length of bore portion 114.Members 104, 106 and 108 are positioned within axial bore portion 114and are maintained in a desired rotational orientation relative to oneanother by pins 126 and 128 extending from forward surface portions 130and 132, respectively, of first tip member 104 into the rearwardlyfacing ends of through openings 134 and 136, respectively, in second tipmember 106, and by pins 138 and 140 extending from rear surface portions142 and 144, respectively (FIGS. 18-20) of die member 108 into theforward ends of openings 134 and 136. Members 104, 106 and 108 aremaintained in a desired rotational orientation with respect to axialbore portion 114 by pin 145 extending through axial opening 146 (FIG.11) in body 102 into opening 148 in first tip member 104.

First tip member 104 is shown individually in FIGS. 12-14, wherein theaforementioned features may be more clearly seen. In addition, it willbe seen that first tip member 104 has a central opening 150 the forwardportion of which is surrounded by tip or protrusion 152. Opening 150 hasa diameter d₅ at its forward end and protrusion 152 has an outsidediameter d₆ (FIG. 14). A portion of the periphery of first tip member104 is cut away to form groove 154 of arcuate cross section extendingfrom forward surface portion--to cylindrical surface portion 156. Groove154 extends from a mid-point adjacent pin 126 in both directions aboutthe periphery of first tip member 104 to meet surface portions 158 and160 on opposite sides of opening 150. As best seen in FIG. 14, surfaceportions 158 and 160 taper in a direction toward the forward side fromthe outer periphery of first tip member 104 to merge with the base ofprotrusion 152. First tip member 104 has a flat, rear surface 162portions of which adjacent the periphery contact surface 118 of body 102in the assembled condition of the elements.

Second tip member 106 is shown individually in FIGS. 15-18. Centralopening 164 has a diameter d₇ at rear surface portions 166 and 168 andtapers inwardly to merge with a second to constant diameter d₈,surrounded by protrusion 170 having an outside diameter d₉. Groove 172extends in an arcuate surface from rear surface portion 166 tocylindrical peripheral surface 174, in both directions from a mid-pointadjacent opening 134 to merge with surface portions 176 and 178 onopposite sides of opening 164. Groove 180 extends in an arcuate surfacefrom forward surface portion 182 to peripheral surface 174 in bothdirections from a mid-point adjacent opening 136 to merge with surfaceportions 184 and 186 on opposite sides of opening 164. Surface portions176 and 178 taper forwardly and surface portions 184 and 186 rearwardlyfrom the periphery of second tip member 106 toward opening 164.

Die member 108 is shown individually in FIGS. 19-21. Central opening 190has a diameter d₁₀ at rear surface portions 142 and 144, and a diameterd₁₁, at front surface 192. Groove 194 extends in an arcuate surface fromrear surface portion 144 to cylindrical peripheral surface 196, from amid-point adjacent opening 140 in both directions about the periphery ofdie member 108 to merge with surface portions 198 and 199 which taper ina direction toward the rear from the outer periphery of the die memberto opening 190. As in central opening 70 of die member 16, opening 190has sections of constant diameter immediately adjacent both the frontand rear surface portions which merge with a central conical or taperedportion at opposite ends of the latter.

Members 104, 106 and 108 are shown in assembled condition in FIG. 22,and in assembled condition with body 102 in FIG. 11. Forward surfaceportions 130 and 132 of first tip member 104 are in opposed, contactingrelation with rear surface portions 166 and 168 of second tip member106, and forward surface portions 182 and 183 of second tip member 106are in contact with rear surface portions 142 and 144 of die member 108.Portions of die member front surface 192 and first tip member rearsurface 162 adjacent the peripheries thereof are engaged by coverportion 110 and surface 118, respectively, to retain members 104, 106and 108 axially fixed within body portion 102. Rotational orientation,as previously explained, is maintained by pins 126, 128, 138, 140 and145 extending into openings 134, 136 and 148.

When so positioned, grooves 154 and 172 in first and second tip members104 and 106, respectively, are directly adjacent one another and combineto form a unitary groove of semi-circular cross section, as seen andindicated by reference numeral 195 in FIG. 11. Likewise, groove 180 ofsecond tip member 106 is immediately adjacent groove 196 of die member108, and the two grooves combine to form the unitary groove 197 alsoseen in FIG. 11. Groove 195 and the adjacent portion of axial boresection 114 combine to form a first, enclosed passageway extending inboth directions from the inner end of radial bore 122 to communicate atone end with the space between tapered surfaces 160 and 176 and at theother end with the space between tapered surfaces 158 and 178 of firstand second tip members 104 and 106. Groove 197 and the adjacent portionof axial bore section 114 combine to form a second, enclosed passagewayextending in both directions from the inner end of radial bore 124 tocommunicate at one end with the space between tapered surfaces 184 and199 and at the other end with the space between tapered surfaces 186 and198 of second tip member 106 and die member 108, respectively.

As best seen in FIG. 22, when members 104, 106 and 108 are in assembledrelation, protrusion 152 of first tip member 104 extends through bothopening 164 of second tip member 106 and opening 190 od die member 108.The difference in diameters provides an annular space between theoutside of the terminal end of protrusion 152 and the inner surface ofprotrusion 170. Thus, coating material C₁ entering through radialopening 122 (or the conduit connected thereto) flows in both directionsabout groove 195 through the first, enclosed passageway, into the spacesbetween the opposed, tapered surfaces on the front side of first tipmember 104 and the rear side of second tip member 106, and through theannular space between the outer and inner surfaces of protrusions 152and 170, respectively, to be deposited uniformly on the surface of wireW₁ as the latter moves axially through die apparatus 100. Wire W₁ has adiameter closely approximating diameter d₅ and is thus guided coaxiallyof members 104, 106 and 108 by first tip member 104.

Protrusion 170 extends forwardly through opening 190 in die member 108with the difference in diameters providing an annular space between theprotrusion outer surface and the adjacent surface of the opening. Thus,coating material C₂ entering through radial opening 124 (or the conduitconnected thereto) flows in both directions about groove 197 through thesecond, enclosed passageway, into the spaces between the opposed,tapered surfaces on the forward side of second tip member 106 and therear side of die member 108, and through the annular space between theouter surface of protrusion 170 and the surrounding surface of opening190 to be deposited in a uniform layer on coating material C₁.

It is thus apparent that the die apparatus construction of FIGS. 10-22is adapted to apply two, concentric, superposed layers of coatingmaterials to a wire moved axially through the apparatus. The thicknessof each layer is determined by the radial dimensions of the annularspaces through which the first and second coating materials flow to bedeposited upon the wire and the first coating layer, respectively. Suchoperating parameters as temperatures and pressures of the coatingmaterials, speed of movement of the wire through the apparatus, etc. maybe determined in conventional manner by those familiar with cross-headdie coating operations.

From the foregoing description, it is apparent how the principles of theinvention may be employed to apply both single and multiple coatinglayers to a single strand of wire. An embodiment shown in FIGS. 23 and24 illustrate use of these principles in applying a coating material ina unitary manner to a plurality of spaced, parallel wires. Such anapplication of principles of the invention is useful, for example, inthe fabrication of so-called flat ribbon cables. From the previouslydescribed embodiments, it may be seen how multiple coating layers couldbe applied to a plurality of parallel wires.

An embodiment of tip and die members incorporating principles of theinvention to produce a multi-strand cable, i.e., a plurality of wires inspaced, parallel relation with a unitary, single layer of coatingmaterial, is shown in FIGS. 23 and 24. Tip member 200 is of the samerelatively flat, wafer-like configuration as previously described tipmembers 14, 104 and 106, having cylindrical peripheral surface 202 withan axial length which is small relative to its diameter. As in theprevious embodiments, tip member 200 includes peripheral groove 204 inthe form of an arcuate surface extending between forward surface portion206 and peripheral surface 202, centrally disposed, laterally elongatedopening 208 surrounded over a portion of its length by forwardlyextending protrusion 210, and surface portions 212 and 214 taperingforwardly from the periphery toward the center of tip member 200.

Die member 216 likewise has a construction and configuration analagousto that of die members 16 and 108, including cylindrical peripheralsurface 218, flat forward surface 220 and central opening 222. Althoughnot fully seen, it will be understood that die member 216 includesrearwardly facing peripheral groove 224, as well as a plurality of rearsurface portions some of which are perpendicularly disposed and othersof which are angularly disposed (tapered) with respect to the axis ofopening 222, as in the previous embodiments. Also, tip and die members200 and 216 are maintained in a desired rotational orientation relativeto one another by pins 226 and 228 on tip member 200 extending intoopenings 230 and 232, respectively, and relative to the axial bore of abody portion of the apparatus by a locator pin extending into alignednotches 234 and 236 in the peripheries of the tip and die members,respectively.

It will be noted that essentially the only difference between tip anddie members 14 and 16 and tip and die members 200 and 216, respectively,is the shape of the central openings and the protrusion on the tipmember. That is, the openings and protrusion of the previously describedembodiment are of circular cross section since a coating of circularcross section to a wire of circular cross section, whereas protrusion210 and opening 222 of tip and die members 200 and 216, respectively,are of substantially oval configuration. Opening 208 of tip member 200has a plurality of circular portions 208' which are mutually joined toform a unitary opening of generally oval configuration.

In operation, tip and die members 200 and 216 are placed with respectiveforward and rear surface portions in mutual contact in the relativerotational orientation provided by pins 226, 228 and openings 230, 232.Protrusion 210 extends into opening 222 with the difference indimensions providing an oval-shaped, annular space surrounding wires W₃,W₄ and W₅ as the latter move axially at equal speed through circularportions 208' of opening 208. Tip and die members 200 and 216 are, ofcourse, positioned within a section of the through axial bore of thebody of die apparatus as in the previously described embodiment. Thebody has the same radial bore for flow of coating material into theaxial bore and the tip and die members are cooperatively positioned toprovide flow passages to the annular space between protrusion 210 andopening 222 in the same manner as previously described. That is,peripheral grooves 204 and 224 combine to form a unitary groove whichcooperates with adjacent portions of the body axial bore to provide anenclosed passageway communicating at opposite ends with the spacesbetween the opposed, spaced surfaces of the tip and die members whichtaper toward one another from the peripheries toward the center, andthence with the annular space through which coating material C₄ isdeposited upon wires W₃, W₄ and W₅.

The outer, cross-sectional configuration of coating material C₄ is, ofcourse, determined by the configuration of opening 222. Although thisconfiguration will in any event be oblong, having a width greater thanits height, it need not be of the oval shape shown in FIGS. 23 and 24.The coating material will normally surround each of the laterally spacedwires and may include longitudinal grooves in its outer surface betweeneach pair of adjacent wires, as is conventional with many flat ribboncables having a plurality of mutually insulated conductors. From theforegoing description, it will be readily understood that the tip anddie members may be designed to accommodate essentially any desirednumber and size of wires and to which single or multiple layers ofcoating materials may be applied.

What is claimed is:
 1. A die member for positioning in cross-head die apparatus for applying a layer of flowable coating material to an elongated, filamentary member moving axially through said die member and a cooperating tip member, said die member comprising a unitary blank including a cylindrical peripheral surface of predetermined diameter and circumference, front and rear surface portions in respective, first and second spaced, parallel planes, a through central opening extending between said first and second planes said cylindrical surface extending between said first and second planes over a first portion of said circumference and from said first plane for a portion of the distance to said second plane over a second portion of said circumference, and a peripheral groove formed as a continuous surface having an arcuate cross-section extending between said cylindrical surface and said second plane over said second portion of said circumference.
 2. The die member of claim 1 wherein said through opening is circular at both said first and second planes.
 3. The die member of claim 1 wherein said opening is of oblong configuration over at least a portion of its axial length including at said first plane.
 4. The die member of claim 1 wherein said opening has a central axis perpendicular to said first and second planes.
 5. The die member of claim 4 wherein said axis is coaxial with said cylindrical surface.
 6. The die member of claim 1 wherein said continuous surface is of arcuate cross section.
 7. The die member of claim 1 wherein said groove extends between opposite ends about a portion of the circumference of said blank.
 8. The die member of claim 7 wherein said rear surface portions lying in said second plane are separated by a pair of recessed surface portions respectively communicating with said opposite ends of said groove and each communicating with said opening. 